1. Technical Field
The present invention relates to a method for determining bag sizes and case pack configurations for form and fill bags and, in particular, to determining bag sizings without the need for sizing trials by using empirical relationships developed from sizing trials for specific products, fixing a bag width, and then determining an appropriate bag length. The method also cross-checks the determined bag size for economical case pack configuration. The method allows for a quick determination of the appropriate bag size for food or like products (such as tortilla or potato chips) that is adequately large to allow for mechanical sealing of the bag without excess non-functional slack fill. By eliminating the need for sizing trials, bag sizing and case pack configurations can be determined quickly, accurately, and inexpensively.
2. Description of Related Art
It is standard practice in the retail food industry for snack foods and like products to be packaged in flexible bags which in turn are consolidated into case packs, typically cardboard boxes, for distribution to retail outlets. The bags are filled with product, such as potato chips, by use of a form and fill machine by methods well-known in the industry. In sizing a particular bag to accommodate a certain weight of product, the bag must be large enough to accommodate the product that falls into it without interfering with the mechanical sealing of the bag by the form and fill machine. Conversely, the bag should not be so large as to include unnecessary dead space or non-functional slack fill. This excessive slack fill not only gives the bag the appearance of not containing an adequate amount of product, but also might run afoul of certain relevant government regulations.
It is not unusual for a product manufacturer to offer the same product, such as a particular line or brand of potato chips, in multiple weight classes requiring different bag sizes for each class. For example, a specific line of potato chips might be offered in a 1-oz. small bag class intended primarily for vending machines, a 1 to 2-oz. single-serving bag class offered for sale primarily in a retail food setting, a 5-oz. bag for a larger class package offered primarily in retail food settings or convenience store settings, several large bag classes ranging from 8-oz. to 20-oz. offered for sale primarily in retail grocery outlets, and a wholesale restaurant class bag of 20 to 25 oz. In fact, it is not unusual for a retail chip manufacturer to break bag sizes down into seven or more classes and offer numerous individual product lines of varying weights within each class.
Product weight, and consequently appropriate bag size, frequently changes within each weight class for each individual product due to a number of factors. Reasons for varying the bag sizes over time are complex and involve a number of factors ranging from purely marketing or promotional considerations to pricing and economics. A weight change might be made to accommodate various regional expectations or in response to other market forces. Weight changes might be made to address consumer preferences or to implement a new pricing model. In order to remain competitive, a snack food manufacturer must be prepared to quickly address the needs of the marketplace and adjust bag sizes quickly and efficiently. It is not unusual for snack food companies to conduct hundreds of bag resizing trials for a variety of products during a single year. A historical database on the selected closed bag volume versus both product volume and product weight for many product lines can be accumulated as a result of such trials, but in the past such information has been of little use in determining a new, unique bag size for a given product.
Instead, each individual resizing project in the past has involved more art than science. Certain bag parameters, such as a permissible range of length-to-width ratios, are fixed. However, the ultimate bag size has usually been determined by conducting physical trials involving guess work and actual physical testing of proposed bag sizes until an acceptable size is determined.
Typically, a decision is made to change the weight of a specific product line within a specific sales class. Once the weight has been determined, several different bag sizes are experimented with to determine an ideal size that can both accommodate the product using standard form and fill machines and minimize slack fill. It may be necessary to adjust a starting bag size length and width numerous times until the appropriate bag size has been found. These experiments usually take place at a packaging plant and require a dedicated form and fill machine to physically make each proposed bag size until an acceptable bag size is found.
A further consideration may be the number of bags that can fit into a single shipping container or case pack. Once the bag size is determined, a suitable case pack configuration must be determined. An appropriate bag size might be determined during bag sizing trials that does not provide for an economical case pack arrangement. For example, after a bag size is determined from a sizing trial, it may be that further shortening of the bag would increase the number of bags accommodated by a single standard size case pack from 11 to 12. The economics of being able to add one additional bag to a case pack (which relates to xe2x80x9ctransportation efficienciesxe2x80x9d) might justify further bag sizing trials in order to develop a different size bag. Further, automatic case packing machines require certain bag orientations and packing efficiencies that require consideration.
In light of the above, it is not unusual for an individual bag sizing trial to take in excess of 40 man hours, a dedicated form and fill machine, and other indirect productivity losses before arriving at a suitable bag size and case pack configuration. Occasionally a bag size is determined by this hit and miss method of the prior art which is determined to be unacceptable once it goes into production, in which case the entire process starts anew with a resizing effort.
Accordingly, a need exists for a method of determining a bag size and related case pack configuration without the need for conducting sizing trials. This method should provide a quick and accurate determination of appropriate bag sizes and case pack configurations across a broad spectrum of bag classes. Ideally, the method should provide decision information to efficiently analyze the various cost and material factors involved. By eliminating the need for sizing trials, the method should greatly reduce the costs involved in changing bag sizes. Further, the method should insure the case pack compatibility with automation features and eliminate the need for resizing bags due to improved accuracy.
The present invention comprises a method for determining bag sizes and case pack configurations by first determining an appropriate bag length by performing a sequence of calculations relying on various empirically determined factors. The bag length calculated is then confirmed against a known empirical relationship and, if necessary, follow-up iteration of the calculations can be made to adjust previously assumed factors. Once the bag length is satisfactorily confirmed, bag sizing can then be compared to various case pack configurations by making another sequence of calculations. If necessary, the bag sizing can then be adjusted for case pack consideration.
The ability to quickly and accurately determine bag sizing eliminates timely and costly bag sizing trials as well as more accurately predicts the required bag size. Further, bag sizing can be easily adjusted in the event that case pack configurations or other considerations require modifications in the bag sizing. Since bag sizes and case pack configuration can be quickly determined and compared, the model is ideally suited for making fine-tuned adjustments to bag sizes and case pack configurations to optimize economic efficiencies. Complete sizing trials can be done in a very short time period, with a reduced chance for error, while also providing enhanced bag quality.